It's not space science, just observation

CHENNAI: It was not science but a thorough pixel-by-pixel comparison of nearly 30 images that helped Chennai technician Shanmuga Subramanian detect the debris of the Vikram landing module after it crashed on the lunar surface on September 7.

The 33-year-old man, who came from, woke up Tuesday with an email from NASA confirming that the US space agency confirmed the location of the Vikram accident and gave him credit for the discovery.

I saw the debris about 0.75 km north of the expected landing location of the landing module. All I did was a basic comparison of apples with apples of two images at a time on the computer screen. Without software or complex calculations, just an old-school method, said the mechanical engineer and programmer that his friends call Shan. It did not require much science, but a basic understanding of the lunar days and nights and the surface of the Moon , he said.

A day after Vikram went missing, Isro said it had located the lander, but did not publish any image. Nasa’s analysis of its (LRO) images too did not reveal any impact scar on the lunar surface. Shan downloaded a 1.5GB resolution image of the region on the Moon published by Nasa on September 17 and compared it with nearly 30 old images captured by the LRO which has been circling the Moon for a decade, with a 1.25m resolution per pixel. Some simple calculations with data on the lander’s path and last known velocity available on the public domain, Shan decided to search for the debris on the north side.

“During the landing, a few radio astronomers had tweeted that the lander had crossed the north pole. With that, I figured out that the debris must be within a 2km x 2km area north of the landing spot , he said. Placing two ‘before’ and ‘after’ images on his screen, Shan zoomed in pixel by pixel and compared. When he noticed a white speck on the new image that was not visible in the old images, he knew it. “There is a definite difference that you can tell between a man-made object and others. For instance, a man-made object would be less illuminated and smaller than a boulder , he said.

Graduated from Government Engineering College, Shan is a climate and space enthusiast. His phone has not stopped ringing since Tuesday morning when he published the email from NASA on his social networking site.